Aspirin not an effective treatment for atrial fibrillation, study suggests

New research suggests that aspirin may not be as effective as previously believed for treating patients with atrial fibrillation. In fact, for patients who had a catheter ablation to lower their risk of stroke, the risks of using aspirin may outweigh the benefits.

Atrial fibrillation (A-fib) is a common heart condition in which the heart beats irregularly. A-fib affects more than 2.7 million people in the United States and, if left untreated, the condition can lead to more serious cardiovascular events - such as stroke, blood clots, or even heart failure.

The most common route for treating patients with A-fib is prescribing anticoagulants, or blood thinners. Some people with A-fib may also have a catheter ablation - a medical procedure that uses energy to damage a small part of heart tissue, thus stopping abnormal electrical signals from traveling through the heart.

Some of the risks entailed by cardiac catheter ablation include bleeding or blood vessel damage. On the plus side, the long-term risk of stroke in patients with A-fib who have undergone the surgery is lower than in patients who did not have an ablation.

However, as Dr. Jared Bunch - the lead author of the new research - explains, when patients with A-fib have had an ablation and also have a low risk of stroke, physicians prefer to treat them with aspirin instead of blood thinners in order to further reduce the risk of stroke.

In the new study, Dr. Bunch and his colleagues examine the effect of long-term aspirin use on patients with A-fib who underwent an ablation.

Putting their new research into perspective, Dr. Bunch explains, "What was unknown was if aspirin was a safe and effective stroke prevention treatment after an ablation in lower-risk AF [atrial fibrillation] patients. Traditionally, lower-risk AF patients have been treated with aspirin without significant supportive data."

In fact, the American College of Cardiologists report that more than 1 in 3 patients with A-fib who have an "intermediate-to-high" risk of stroke are treated with aspirin instead of oral blood thinners, even when medical guidelines advise the use of anticoagulants.

The results of the new study were presented at Heart Rhythm 2017, the Heart Rhythm Society's 38th Annual Scientific Sessions, held in Chicago, IL.

Aspirin has 'little to no benefit for stroke prevention' in patients with A-fib

The study examined 4,124 patients with A-fib over a period of 3 years. The participants had a low risk of stroke, and they had undergone catheter ablation.

Dr. Bunch and colleagues found that patients who were prescribed aspirin were significantly more likely to have gastrointestinal and genitourinary bleeding than those who took anticoagulants such as warfarin, or compared with those who did not receive any treatment.

The study's lead author reports on the findings:

"In both the general and medical communities, aspirin therapy is perceived to reduce risks, it's easy to prescribe, and it's available worldwide over-the-counter. There's always been little evidence to support its use for stroke prevention in AF patients. This study continues to show that aspirin has little to no benefit for stroke prevention in AF patients and when used in low-risk patients it significantly increases a patient's bleeding risk."

Dr. Jared Bunch

Additionally, the study emphasizes aspirin's lack of benefit for patients with A-fib who had catheter ablation, as well as the increased risk of bleeding that comes with aspirin use, particularly when the risk of stroke is reduced by the surgery.

Dr. Bunch further comments on the significance of the results, saying, "Aspirin is widely considered a healthy therapy to lower risk of heart disease [...] Like all therapies, it has significant risks, including major bleeding. Unfortunately, after careful study, it doesn't significantly lower stroke risk in most AF patients. Since stroke is the most feared complication of AF, we need to continue to study all available therapies to understand the most effective and safest treatment choices and how to use them after ablation."

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